1/* 2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "c1/c1_Compilation.hpp" 27#include "c1/c1_FrameMap.hpp" 28#include "c1/c1_GraphBuilder.hpp" 29#include "c1/c1_IR.hpp" 30#include "c1/c1_InstructionPrinter.hpp" 31#include "c1/c1_Optimizer.hpp" 32#include "memory/resourceArea.hpp" 33#include "utilities/bitMap.inline.hpp" 34 35 36// Implementation of XHandlers 37// 38// Note: This code could eventually go away if we are 39// just using the ciExceptionHandlerStream. 40 41XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { 42 ciExceptionHandlerStream s(method); 43 while (!s.is_done()) { 44 _list.append(new XHandler(s.handler())); 45 s.next(); 46 } 47 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); 48} 49 50// deep copy of all XHandler contained in list 51XHandlers::XHandlers(XHandlers* other) : 52 _list(other->length()) 53{ 54 for (int i = 0; i < other->length(); i++) { 55 _list.append(new XHandler(other->handler_at(i))); 56 } 57} 58 59// Returns whether a particular exception type can be caught. Also 60// returns true if klass is unloaded or any exception handler 61// classes are unloaded. type_is_exact indicates whether the throw 62// is known to be exactly that class or it might throw a subtype. 63bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { 64 // the type is unknown so be conservative 65 if (!klass->is_loaded()) { 66 return true; 67 } 68 69 for (int i = 0; i < length(); i++) { 70 XHandler* handler = handler_at(i); 71 if (handler->is_catch_all()) { 72 // catch of ANY 73 return true; 74 } 75 ciInstanceKlass* handler_klass = handler->catch_klass(); 76 // if it's unknown it might be catchable 77 if (!handler_klass->is_loaded()) { 78 return true; 79 } 80 // if the throw type is definitely a subtype of the catch type 81 // then it can be caught. 82 if (klass->is_subtype_of(handler_klass)) { 83 return true; 84 } 85 if (!type_is_exact) { 86 // If the type isn't exactly known then it can also be caught by 87 // catch statements where the inexact type is a subtype of the 88 // catch type. 89 // given: foo extends bar extends Exception 90 // throw bar can be caught by catch foo, catch bar, and catch 91 // Exception, however it can't be caught by any handlers without 92 // bar in its type hierarchy. 93 if (handler_klass->is_subtype_of(klass)) { 94 return true; 95 } 96 } 97 } 98 99 return false; 100} 101 102 103bool XHandlers::equals(XHandlers* others) const { 104 if (others == NULL) return false; 105 if (length() != others->length()) return false; 106 107 for (int i = 0; i < length(); i++) { 108 if (!handler_at(i)->equals(others->handler_at(i))) return false; 109 } 110 return true; 111} 112 113bool XHandler::equals(XHandler* other) const { 114 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); 115 116 if (entry_pco() != other->entry_pco()) return false; 117 if (scope_count() != other->scope_count()) return false; 118 if (_desc != other->_desc) return false; 119 120 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); 121 return true; 122} 123 124 125// Implementation of IRScope 126BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { 127 GraphBuilder gm(compilation, this); 128 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); 129 if (compilation->bailed_out()) return NULL; 130 return gm.start(); 131} 132 133 134IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) 135: _callees(2) 136, _compilation(compilation) 137, _requires_phi_function(method->max_locals()) 138{ 139 _caller = caller; 140 _level = caller == NULL ? 0 : caller->level() + 1; 141 _method = method; 142 _xhandlers = new XHandlers(method); 143 _number_of_locks = 0; 144 _monitor_pairing_ok = method->has_balanced_monitors(); 145 _wrote_final = false; 146 _wrote_fields = false; 147 _wrote_volatile = false; 148 _start = NULL; 149 150 if (osr_bci != -1) { 151 // selective creation of phi functions is not possibel in osr-methods 152 _requires_phi_function.set_range(0, method->max_locals()); 153 } 154 155 assert(method->holder()->is_loaded() , "method holder must be loaded"); 156 157 // build graph if monitor pairing is ok 158 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); 159} 160 161 162int IRScope::max_stack() const { 163 int my_max = method()->max_stack(); 164 int callee_max = 0; 165 for (int i = 0; i < number_of_callees(); i++) { 166 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); 167 } 168 return my_max + callee_max; 169} 170 171 172bool IRScopeDebugInfo::should_reexecute() { 173 ciMethod* cur_method = scope()->method(); 174 int cur_bci = bci(); 175 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) { 176 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci); 177 return Interpreter::bytecode_should_reexecute(code); 178 } else 179 return false; 180} 181 182 183// Implementation of CodeEmitInfo 184 185// Stack must be NON-null 186CodeEmitInfo::CodeEmitInfo(ValueStack* stack, XHandlers* exception_handlers, bool deoptimize_on_exception) 187 : _scope(stack->scope()) 188 , _scope_debug_info(NULL) 189 , _oop_map(NULL) 190 , _stack(stack) 191 , _exception_handlers(exception_handlers) 192 , _is_method_handle_invoke(false) 193 , _deoptimize_on_exception(deoptimize_on_exception) { 194 assert(_stack != NULL, "must be non null"); 195} 196 197 198CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, ValueStack* stack) 199 : _scope(info->_scope) 200 , _exception_handlers(NULL) 201 , _scope_debug_info(NULL) 202 , _oop_map(NULL) 203 , _stack(stack == NULL ? info->_stack : stack) 204 , _is_method_handle_invoke(info->_is_method_handle_invoke) 205 , _deoptimize_on_exception(info->_deoptimize_on_exception) { 206 207 // deep copy of exception handlers 208 if (info->_exception_handlers != NULL) { 209 _exception_handlers = new XHandlers(info->_exception_handlers); 210 } 211} 212 213 214void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) { 215 // record the safepoint before recording the debug info for enclosing scopes 216 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); 217 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, _is_method_handle_invoke); 218 recorder->end_safepoint(pc_offset); 219} 220 221 222void CodeEmitInfo::add_register_oop(LIR_Opr opr) { 223 assert(_oop_map != NULL, "oop map must already exist"); 224 assert(opr->is_single_cpu(), "should not call otherwise"); 225 226 VMReg name = frame_map()->regname(opr); 227 _oop_map->set_oop(name); 228} 229 230// Mirror the stack size calculation in the deopt code 231// How much stack space would we need at this point in the program in 232// case of deoptimization? 233int CodeEmitInfo::interpreter_frame_size() const { 234 ValueStack* state = _stack; 235 int size = 0; 236 int callee_parameters = 0; 237 int callee_locals = 0; 238 int extra_args = state->scope()->method()->max_stack() - state->stack_size(); 239 240 while (state != NULL) { 241 int locks = state->locks_size(); 242 int temps = state->stack_size(); 243 bool is_top_frame = (state == _stack); 244 ciMethod* method = state->scope()->method(); 245 246 int frame_size = BytesPerWord * Interpreter::size_activation(method->max_stack(), 247 temps + callee_parameters, 248 extra_args, 249 locks, 250 callee_parameters, 251 callee_locals, 252 is_top_frame); 253 size += frame_size; 254 255 callee_parameters = method->size_of_parameters(); 256 callee_locals = method->max_locals(); 257 extra_args = 0; 258 state = state->caller_state(); 259 } 260 return size + Deoptimization::last_frame_adjust(0, callee_locals) * BytesPerWord; 261} 262 263// Implementation of IR 264 265IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : 266 _num_loops(0) { 267 // setup IR fields 268 _compilation = compilation; 269 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); 270 _code = NULL; 271} 272 273 274void IR::optimize_blocks() { 275 Optimizer opt(this); 276 if (!compilation()->profile_branches()) { 277 if (DoCEE) { 278 opt.eliminate_conditional_expressions(); 279#ifndef PRODUCT 280 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } 281 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } 282#endif 283 } 284 if (EliminateBlocks) { 285 opt.eliminate_blocks(); 286#ifndef PRODUCT 287 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } 288 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } 289#endif 290 } 291 } 292} 293 294void IR::eliminate_null_checks() { 295 Optimizer opt(this); 296 if (EliminateNullChecks) { 297 opt.eliminate_null_checks(); 298#ifndef PRODUCT 299 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } 300 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } 301#endif 302 } 303} 304 305 306static int sort_pairs(BlockPair** a, BlockPair** b) { 307 if ((*a)->from() == (*b)->from()) { 308 return (*a)->to()->block_id() - (*b)->to()->block_id(); 309 } else { 310 return (*a)->from()->block_id() - (*b)->from()->block_id(); 311 } 312} 313 314 315class CriticalEdgeFinder: public BlockClosure { 316 BlockPairList blocks; 317 IR* _ir; 318 319 public: 320 CriticalEdgeFinder(IR* ir): _ir(ir) {} 321 void block_do(BlockBegin* bb) { 322 BlockEnd* be = bb->end(); 323 int nos = be->number_of_sux(); 324 if (nos >= 2) { 325 for (int i = 0; i < nos; i++) { 326 BlockBegin* sux = be->sux_at(i); 327 if (sux->number_of_preds() >= 2) { 328 blocks.append(new BlockPair(bb, sux)); 329 } 330 } 331 } 332 } 333 334 void split_edges() { 335 BlockPair* last_pair = NULL; 336 blocks.sort(sort_pairs); 337 for (int i = 0; i < blocks.length(); i++) { 338 BlockPair* pair = blocks.at(i); 339 if (last_pair != NULL && pair->is_same(last_pair)) continue; 340 BlockBegin* from = pair->from(); 341 BlockBegin* to = pair->to(); 342 BlockBegin* split = from->insert_block_between(to); 343#ifndef PRODUCT 344 if ((PrintIR || PrintIR1) && Verbose) { 345 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", 346 from->block_id(), to->block_id(), split->block_id()); 347 } 348#endif 349 last_pair = pair; 350 } 351 } 352}; 353 354void IR::split_critical_edges() { 355 CriticalEdgeFinder cef(this); 356 357 iterate_preorder(&cef); 358 cef.split_edges(); 359} 360 361 362class UseCountComputer: public ValueVisitor, BlockClosure { 363 private: 364 void visit(Value* n) { 365 // Local instructions and Phis for expression stack values at the 366 // start of basic blocks are not added to the instruction list 367 if (!(*n)->is_linked() && (*n)->can_be_linked()) { 368 assert(false, "a node was not appended to the graph"); 369 Compilation::current()->bailout("a node was not appended to the graph"); 370 } 371 // use n's input if not visited before 372 if (!(*n)->is_pinned() && !(*n)->has_uses()) { 373 // note: a) if the instruction is pinned, it will be handled by compute_use_count 374 // b) if the instruction has uses, it was touched before 375 // => in both cases we don't need to update n's values 376 uses_do(n); 377 } 378 // use n 379 (*n)->_use_count++; 380 } 381 382 Values* worklist; 383 int depth; 384 enum { 385 max_recurse_depth = 20 386 }; 387 388 void uses_do(Value* n) { 389 depth++; 390 if (depth > max_recurse_depth) { 391 // don't allow the traversal to recurse too deeply 392 worklist->push(*n); 393 } else { 394 (*n)->input_values_do(this); 395 // special handling for some instructions 396 if ((*n)->as_BlockEnd() != NULL) { 397 // note on BlockEnd: 398 // must 'use' the stack only if the method doesn't 399 // terminate, however, in those cases stack is empty 400 (*n)->state_values_do(this); 401 } 402 } 403 depth--; 404 } 405 406 void block_do(BlockBegin* b) { 407 depth = 0; 408 // process all pinned nodes as the roots of expression trees 409 for (Instruction* n = b; n != NULL; n = n->next()) { 410 if (n->is_pinned()) uses_do(&n); 411 } 412 assert(depth == 0, "should have counted back down"); 413 414 // now process any unpinned nodes which recursed too deeply 415 while (worklist->length() > 0) { 416 Value t = worklist->pop(); 417 if (!t->is_pinned()) { 418 // compute the use count 419 uses_do(&t); 420 421 // pin the instruction so that LIRGenerator doesn't recurse 422 // too deeply during it's evaluation. 423 t->pin(); 424 } 425 } 426 assert(depth == 0, "should have counted back down"); 427 } 428 429 UseCountComputer() { 430 worklist = new Values(); 431 depth = 0; 432 } 433 434 public: 435 static void compute(BlockList* blocks) { 436 UseCountComputer ucc; 437 blocks->iterate_backward(&ucc); 438 } 439}; 440 441 442// helper macro for short definition of trace-output inside code 443#ifndef PRODUCT 444 #define TRACE_LINEAR_SCAN(level, code) \ 445 if (TraceLinearScanLevel >= level) { \ 446 code; \ 447 } 448#else 449 #define TRACE_LINEAR_SCAN(level, code) 450#endif 451 452class ComputeLinearScanOrder : public StackObj { 453 private: 454 int _max_block_id; // the highest block_id of a block 455 int _num_blocks; // total number of blocks (smaller than _max_block_id) 456 int _num_loops; // total number of loops 457 bool _iterative_dominators;// method requires iterative computation of dominatiors 458 459 BlockList* _linear_scan_order; // the resulting list of blocks in correct order 460 461 ResourceBitMap _visited_blocks; // used for recursive processing of blocks 462 ResourceBitMap _active_blocks; // used for recursive processing of blocks 463 ResourceBitMap _dominator_blocks; // temproary BitMap used for computation of dominator 464 intArray _forward_branches; // number of incoming forward branches for each block 465 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges 466 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop 467 BlockList _work_list; // temporary list (used in mark_loops and compute_order) 468 BlockList _loop_headers; 469 470 Compilation* _compilation; 471 472 // accessors for _visited_blocks and _active_blocks 473 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } 474 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } 475 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } 476 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } 477 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } 478 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } 479 480 // accessors for _forward_branches 481 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } 482 int dec_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) - 1); return _forward_branches.at(b->block_id()); } 483 484 // accessors for _loop_map 485 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } 486 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } 487 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } 488 489 // count edges between blocks 490 void count_edges(BlockBegin* cur, BlockBegin* parent); 491 492 // loop detection 493 void mark_loops(); 494 void clear_non_natural_loops(BlockBegin* start_block); 495 void assign_loop_depth(BlockBegin* start_block); 496 497 // computation of final block order 498 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); 499 void compute_dominator(BlockBegin* cur, BlockBegin* parent); 500 int compute_weight(BlockBegin* cur); 501 bool ready_for_processing(BlockBegin* cur); 502 void sort_into_work_list(BlockBegin* b); 503 void append_block(BlockBegin* cur); 504 void compute_order(BlockBegin* start_block); 505 506 // fixup of dominators for non-natural loops 507 bool compute_dominators_iter(); 508 void compute_dominators(); 509 510 // debug functions 511 NOT_PRODUCT(void print_blocks();) 512 DEBUG_ONLY(void verify();) 513 514 Compilation* compilation() const { return _compilation; } 515 public: 516 ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block); 517 518 // accessors for final result 519 BlockList* linear_scan_order() const { return _linear_scan_order; } 520 int num_loops() const { return _num_loops; } 521}; 522 523 524ComputeLinearScanOrder::ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block) : 525 _max_block_id(BlockBegin::number_of_blocks()), 526 _num_blocks(0), 527 _num_loops(0), 528 _iterative_dominators(false), 529 _visited_blocks(_max_block_id), 530 _active_blocks(_max_block_id), 531 _dominator_blocks(_max_block_id), 532 _forward_branches(_max_block_id, _max_block_id, 0), 533 _loop_end_blocks(8), 534 _work_list(8), 535 _linear_scan_order(NULL), // initialized later with correct size 536 _loop_map(0), // initialized later with correct size 537 _compilation(c) 538{ 539 TRACE_LINEAR_SCAN(2, tty->print_cr("***** computing linear-scan block order")); 540 541 count_edges(start_block, NULL); 542 543 if (compilation()->is_profiling()) { 544 ciMethod *method = compilation()->method(); 545 if (!method->is_accessor()) { 546 ciMethodData* md = method->method_data_or_null(); 547 assert(md != NULL, "Sanity"); 548 md->set_compilation_stats(_num_loops, _num_blocks); 549 } 550 } 551 552 if (_num_loops > 0) { 553 mark_loops(); 554 clear_non_natural_loops(start_block); 555 assign_loop_depth(start_block); 556 } 557 558 compute_order(start_block); 559 compute_dominators(); 560 561 NOT_PRODUCT(print_blocks()); 562 DEBUG_ONLY(verify()); 563} 564 565 566// Traverse the CFG: 567// * count total number of blocks 568// * count all incoming edges and backward incoming edges 569// * number loop header blocks 570// * create a list with all loop end blocks 571void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { 572 TRACE_LINEAR_SCAN(3, tty->print_cr("Enter count_edges for block B%d coming from B%d", cur->block_id(), parent != NULL ? parent->block_id() : -1)); 573 assert(cur->dominator() == NULL, "dominator already initialized"); 574 575 if (is_active(cur)) { 576 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); 577 assert(is_visited(cur), "block must be visisted when block is active"); 578 assert(parent != NULL, "must have parent"); 579 580 cur->set(BlockBegin::backward_branch_target_flag); 581 582 // When a loop header is also the start of an exception handler, then the backward branch is 583 // an exception edge. Because such edges are usually critical edges which cannot be split, the 584 // loop must be excluded here from processing. 585 if (cur->is_set(BlockBegin::exception_entry_flag)) { 586 // Make sure that dominators are correct in this weird situation 587 _iterative_dominators = true; 588 return; 589 } 590 591 cur->set(BlockBegin::linear_scan_loop_header_flag); 592 parent->set(BlockBegin::linear_scan_loop_end_flag); 593 594 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, 595 "loop end blocks must have one successor (critical edges are split)"); 596 597 _loop_end_blocks.append(parent); 598 return; 599 } 600 601 // increment number of incoming forward branches 602 inc_forward_branches(cur); 603 604 if (is_visited(cur)) { 605 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); 606 return; 607 } 608 609 _num_blocks++; 610 set_visited(cur); 611 set_active(cur); 612 613 // recursive call for all successors 614 int i; 615 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 616 count_edges(cur->sux_at(i), cur); 617 } 618 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 619 count_edges(cur->exception_handler_at(i), cur); 620 } 621 622 clear_active(cur); 623 624 // Each loop has a unique number. 625 // When multiple loops are nested, assign_loop_depth assumes that the 626 // innermost loop has the lowest number. This is guaranteed by setting 627 // the loop number after the recursive calls for the successors above 628 // have returned. 629 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { 630 assert(cur->loop_index() == -1, "cannot set loop-index twice"); 631 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); 632 633 cur->set_loop_index(_num_loops); 634 _loop_headers.append(cur); 635 _num_loops++; 636 } 637 638 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); 639} 640 641 642void ComputeLinearScanOrder::mark_loops() { 643 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); 644 645 _loop_map = BitMap2D(_num_loops, _max_block_id); 646 647 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { 648 BlockBegin* loop_end = _loop_end_blocks.at(i); 649 BlockBegin* loop_start = loop_end->sux_at(0); 650 int loop_idx = loop_start->loop_index(); 651 652 TRACE_LINEAR_SCAN(3, tty->print_cr("Processing loop from B%d to B%d (loop %d):", loop_start->block_id(), loop_end->block_id(), loop_idx)); 653 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); 654 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); 655 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); 656 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); 657 assert(_work_list.is_empty(), "work list must be empty before processing"); 658 659 // add the end-block of the loop to the working list 660 _work_list.push(loop_end); 661 set_block_in_loop(loop_idx, loop_end); 662 do { 663 BlockBegin* cur = _work_list.pop(); 664 665 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); 666 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); 667 668 // recursive processing of all predecessors ends when start block of loop is reached 669 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { 670 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { 671 BlockBegin* pred = cur->pred_at(j); 672 673 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { 674 // this predecessor has not been processed yet, so add it to work list 675 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); 676 _work_list.push(pred); 677 set_block_in_loop(loop_idx, pred); 678 } 679 } 680 } 681 } while (!_work_list.is_empty()); 682 } 683} 684 685 686// check for non-natural loops (loops where the loop header does not dominate 687// all other loop blocks = loops with mulitple entries). 688// such loops are ignored 689void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { 690 for (int i = _num_loops - 1; i >= 0; i--) { 691 if (is_block_in_loop(i, start_block)) { 692 // loop i contains the entry block of the method 693 // -> this is not a natural loop, so ignore it 694 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); 695 696 BlockBegin *loop_header = _loop_headers.at(i); 697 assert(loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Must be loop header"); 698 699 for (int j = 0; j < loop_header->number_of_preds(); j++) { 700 BlockBegin *pred = loop_header->pred_at(j); 701 pred->clear(BlockBegin::linear_scan_loop_end_flag); 702 } 703 704 loop_header->clear(BlockBegin::linear_scan_loop_header_flag); 705 706 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { 707 clear_block_in_loop(i, block_id); 708 } 709 _iterative_dominators = true; 710 } 711 } 712} 713 714void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { 715 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing loop-depth and weight")); 716 init_visited(); 717 718 assert(_work_list.is_empty(), "work list must be empty before processing"); 719 _work_list.append(start_block); 720 721 do { 722 BlockBegin* cur = _work_list.pop(); 723 724 if (!is_visited(cur)) { 725 set_visited(cur); 726 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); 727 728 // compute loop-depth and loop-index for the block 729 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); 730 int i; 731 int loop_depth = 0; 732 int min_loop_idx = -1; 733 for (i = _num_loops - 1; i >= 0; i--) { 734 if (is_block_in_loop(i, cur)) { 735 loop_depth++; 736 min_loop_idx = i; 737 } 738 } 739 cur->set_loop_depth(loop_depth); 740 cur->set_loop_index(min_loop_idx); 741 742 // append all unvisited successors to work list 743 for (i = cur->number_of_sux() - 1; i >= 0; i--) { 744 _work_list.append(cur->sux_at(i)); 745 } 746 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { 747 _work_list.append(cur->exception_handler_at(i)); 748 } 749 } 750 } while (!_work_list.is_empty()); 751} 752 753 754BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { 755 assert(a != NULL && b != NULL, "must have input blocks"); 756 757 _dominator_blocks.clear(); 758 while (a != NULL) { 759 _dominator_blocks.set_bit(a->block_id()); 760 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); 761 a = a->dominator(); 762 } 763 while (b != NULL && !_dominator_blocks.at(b->block_id())) { 764 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); 765 b = b->dominator(); 766 } 767 768 assert(b != NULL, "could not find dominator"); 769 return b; 770} 771 772void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { 773 if (cur->dominator() == NULL) { 774 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); 775 cur->set_dominator(parent); 776 777 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { 778 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: computing dominator of B%d: common dominator of B%d and B%d is B%d", cur->block_id(), parent->block_id(), cur->dominator()->block_id(), common_dominator(cur->dominator(), parent)->block_id())); 779 // Does not hold for exception blocks 780 assert(cur->number_of_preds() > 1 || cur->is_set(BlockBegin::exception_entry_flag), ""); 781 cur->set_dominator(common_dominator(cur->dominator(), parent)); 782 } 783 784 // Additional edge to xhandler of all our successors 785 // range check elimination needs that the state at the end of a 786 // block be valid in every block it dominates so cur must dominate 787 // the exception handlers of its successors. 788 int num_cur_xhandler = cur->number_of_exception_handlers(); 789 for (int j = 0; j < num_cur_xhandler; j++) { 790 BlockBegin* xhandler = cur->exception_handler_at(j); 791 compute_dominator(xhandler, parent); 792 } 793} 794 795 796int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { 797 BlockBegin* single_sux = NULL; 798 if (cur->number_of_sux() == 1) { 799 single_sux = cur->sux_at(0); 800 } 801 802 // limit loop-depth to 15 bit (only for security reason, it will never be so big) 803 int weight = (cur->loop_depth() & 0x7FFF) << 16; 804 805 // general macro for short definition of weight flags 806 // the first instance of INC_WEIGHT_IF has the highest priority 807 int cur_bit = 15; 808 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; 809 810 // this is necessery for the (very rare) case that two successing blocks have 811 // the same loop depth, but a different loop index (can happen for endless loops 812 // with exception handlers) 813 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); 814 815 // loop end blocks (blocks that end with a backward branch) are added 816 // after all other blocks of the loop. 817 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); 818 819 // critical edge split blocks are prefered because than they have a bigger 820 // proability to be completely empty 821 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); 822 823 // exceptions should not be thrown in normal control flow, so these blocks 824 // are added as late as possible 825 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); 826 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); 827 828 // exceptions handlers are added as late as possible 829 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); 830 831 // guarantee that weight is > 0 832 weight |= 1; 833 834 #undef INC_WEIGHT_IF 835 assert(cur_bit >= 0, "too many flags"); 836 assert(weight > 0, "weight cannot become negative"); 837 838 return weight; 839} 840 841bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { 842 // Discount the edge just traveled. 843 // When the number drops to zero, all forward branches were processed 844 if (dec_forward_branches(cur) != 0) { 845 return false; 846 } 847 848 assert(_linear_scan_order->find(cur) == -1, "block already processed (block can be ready only once)"); 849 assert(_work_list.find(cur) == -1, "block already in work-list (block can be ready only once)"); 850 return true; 851} 852 853void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { 854 assert(_work_list.find(cur) == -1, "block already in work list"); 855 856 int cur_weight = compute_weight(cur); 857 858 // the linear_scan_number is used to cache the weight of a block 859 cur->set_linear_scan_number(cur_weight); 860 861#ifndef PRODUCT 862 if (StressLinearScan) { 863 _work_list.insert_before(0, cur); 864 return; 865 } 866#endif 867 868 _work_list.append(NULL); // provide space for new element 869 870 int insert_idx = _work_list.length() - 1; 871 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { 872 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); 873 insert_idx--; 874 } 875 _work_list.at_put(insert_idx, cur); 876 877 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); 878 TRACE_LINEAR_SCAN(3, for (int i = 0; i < _work_list.length(); i++) tty->print_cr("%8d B%2d weight:%6x", i, _work_list.at(i)->block_id(), _work_list.at(i)->linear_scan_number())); 879 880#ifdef ASSERT 881 for (int i = 0; i < _work_list.length(); i++) { 882 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); 883 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); 884 } 885#endif 886} 887 888void ComputeLinearScanOrder::append_block(BlockBegin* cur) { 889 TRACE_LINEAR_SCAN(3, tty->print_cr("appending block B%d (weight 0x%6x) to linear-scan order", cur->block_id(), cur->linear_scan_number())); 890 assert(_linear_scan_order->find(cur) == -1, "cannot add the same block twice"); 891 892 // currently, the linear scan order and code emit order are equal. 893 // therefore the linear_scan_number and the weight of a block must also 894 // be equal. 895 cur->set_linear_scan_number(_linear_scan_order->length()); 896 _linear_scan_order->append(cur); 897} 898 899void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { 900 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing final block order")); 901 902 // the start block is always the first block in the linear scan order 903 _linear_scan_order = new BlockList(_num_blocks); 904 append_block(start_block); 905 906 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); 907 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); 908 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); 909 910 BlockBegin* sux_of_osr_entry = NULL; 911 if (osr_entry != NULL) { 912 // special handling for osr entry: 913 // ignore the edge between the osr entry and its successor for processing 914 // the osr entry block is added manually below 915 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); 916 assert(osr_entry->sux_at(0)->number_of_preds() >= 2, "sucessor of osr entry must have two predecessors (otherwise it is not present in normal control flow"); 917 918 sux_of_osr_entry = osr_entry->sux_at(0); 919 dec_forward_branches(sux_of_osr_entry); 920 921 compute_dominator(osr_entry, start_block); 922 _iterative_dominators = true; 923 } 924 compute_dominator(std_entry, start_block); 925 926 // start processing with standard entry block 927 assert(_work_list.is_empty(), "list must be empty before processing"); 928 929 if (ready_for_processing(std_entry)) { 930 sort_into_work_list(std_entry); 931 } else { 932 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); 933 } 934 935 do { 936 BlockBegin* cur = _work_list.pop(); 937 938 if (cur == sux_of_osr_entry) { 939 // the osr entry block is ignored in normal processing, it is never added to the 940 // work list. Instead, it is added as late as possible manually here. 941 append_block(osr_entry); 942 compute_dominator(cur, osr_entry); 943 } 944 append_block(cur); 945 946 int i; 947 int num_sux = cur->number_of_sux(); 948 // changed loop order to get "intuitive" order of if- and else-blocks 949 for (i = 0; i < num_sux; i++) { 950 BlockBegin* sux = cur->sux_at(i); 951 compute_dominator(sux, cur); 952 if (ready_for_processing(sux)) { 953 sort_into_work_list(sux); 954 } 955 } 956 num_sux = cur->number_of_exception_handlers(); 957 for (i = 0; i < num_sux; i++) { 958 BlockBegin* sux = cur->exception_handler_at(i); 959 if (ready_for_processing(sux)) { 960 sort_into_work_list(sux); 961 } 962 } 963 } while (_work_list.length() > 0); 964} 965 966 967bool ComputeLinearScanOrder::compute_dominators_iter() { 968 bool changed = false; 969 int num_blocks = _linear_scan_order->length(); 970 971 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); 972 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); 973 for (int i = 1; i < num_blocks; i++) { 974 BlockBegin* block = _linear_scan_order->at(i); 975 976 BlockBegin* dominator = block->pred_at(0); 977 int num_preds = block->number_of_preds(); 978 979 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: Processing B%d", block->block_id())); 980 981 for (int j = 0; j < num_preds; j++) { 982 983 BlockBegin *pred = block->pred_at(j); 984 TRACE_LINEAR_SCAN(4, tty->print_cr(" DOM: Subrocessing B%d", pred->block_id())); 985 986 if (block->is_set(BlockBegin::exception_entry_flag)) { 987 dominator = common_dominator(dominator, pred); 988 int num_pred_preds = pred->number_of_preds(); 989 for (int k = 0; k < num_pred_preds; k++) { 990 dominator = common_dominator(dominator, pred->pred_at(k)); 991 } 992 } else { 993 dominator = common_dominator(dominator, pred); 994 } 995 } 996 997 if (dominator != block->dominator()) { 998 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: updating dominator of B%d from B%d to B%d", block->block_id(), block->dominator()->block_id(), dominator->block_id())); 999 1000 block->set_dominator(dominator); 1001 changed = true; 1002 } 1003 } 1004 return changed; 1005} 1006 1007void ComputeLinearScanOrder::compute_dominators() { 1008 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators)); 1009 1010 // iterative computation of dominators is only required for methods with non-natural loops 1011 // and OSR-methods. For all other methods, the dominators computed when generating the 1012 // linear scan block order are correct. 1013 if (_iterative_dominators) { 1014 do { 1015 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation")); 1016 } while (compute_dominators_iter()); 1017 } 1018 1019 // check that dominators are correct 1020 assert(!compute_dominators_iter(), "fix point not reached"); 1021 1022 // Add Blocks to dominates-Array 1023 int num_blocks = _linear_scan_order->length(); 1024 for (int i = 0; i < num_blocks; i++) { 1025 BlockBegin* block = _linear_scan_order->at(i); 1026 1027 BlockBegin *dom = block->dominator(); 1028 if (dom) { 1029 assert(dom->dominator_depth() != -1, "Dominator must have been visited before"); 1030 dom->dominates()->append(block); 1031 block->set_dominator_depth(dom->dominator_depth() + 1); 1032 } else { 1033 block->set_dominator_depth(0); 1034 } 1035 } 1036} 1037 1038 1039#ifndef PRODUCT 1040void ComputeLinearScanOrder::print_blocks() { 1041 if (TraceLinearScanLevel >= 2) { 1042 tty->print_cr("----- loop information:"); 1043 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 1044 BlockBegin* cur = _linear_scan_order->at(block_idx); 1045 1046 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); 1047 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 1048 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); 1049 } 1050 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); 1051 } 1052 } 1053 1054 if (TraceLinearScanLevel >= 1) { 1055 tty->print_cr("----- linear-scan block order:"); 1056 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { 1057 BlockBegin* cur = _linear_scan_order->at(block_idx); 1058 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); 1059 1060 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); 1061 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); 1062 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); 1063 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); 1064 1065 if (cur->dominator() != NULL) { 1066 tty->print(" dom: B%d ", cur->dominator()->block_id()); 1067 } else { 1068 tty->print(" dom: NULL "); 1069 } 1070 1071 if (cur->number_of_preds() > 0) { 1072 tty->print(" preds: "); 1073 for (int j = 0; j < cur->number_of_preds(); j++) { 1074 BlockBegin* pred = cur->pred_at(j); 1075 tty->print("B%d ", pred->block_id()); 1076 } 1077 } 1078 if (cur->number_of_sux() > 0) { 1079 tty->print(" sux: "); 1080 for (int j = 0; j < cur->number_of_sux(); j++) { 1081 BlockBegin* sux = cur->sux_at(j); 1082 tty->print("B%d ", sux->block_id()); 1083 } 1084 } 1085 if (cur->number_of_exception_handlers() > 0) { 1086 tty->print(" ex: "); 1087 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { 1088 BlockBegin* ex = cur->exception_handler_at(j); 1089 tty->print("B%d ", ex->block_id()); 1090 } 1091 } 1092 tty->cr(); 1093 } 1094 } 1095} 1096#endif 1097 1098#ifdef ASSERT 1099void ComputeLinearScanOrder::verify() { 1100 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); 1101 1102 if (StressLinearScan) { 1103 // blocks are scrambled when StressLinearScan is used 1104 return; 1105 } 1106 1107 // check that all successors of a block have a higher linear-scan-number 1108 // and that all predecessors of a block have a lower linear-scan-number 1109 // (only backward branches of loops are ignored) 1110 int i; 1111 for (i = 0; i < _linear_scan_order->length(); i++) { 1112 BlockBegin* cur = _linear_scan_order->at(i); 1113 1114 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); 1115 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->find(cur), "incorrect linear_scan_number"); 1116 1117 int j; 1118 for (j = cur->number_of_sux() - 1; j >= 0; j--) { 1119 BlockBegin* sux = cur->sux_at(j); 1120 1121 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->find(sux), "incorrect linear_scan_number"); 1122 if (!sux->is_set(BlockBegin::backward_branch_target_flag)) { 1123 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); 1124 } 1125 if (cur->loop_depth() == sux->loop_depth()) { 1126 assert(cur->loop_index() == sux->loop_index() || sux->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); 1127 } 1128 } 1129 1130 for (j = cur->number_of_preds() - 1; j >= 0; j--) { 1131 BlockBegin* pred = cur->pred_at(j); 1132 1133 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->find(pred), "incorrect linear_scan_number"); 1134 if (!cur->is_set(BlockBegin::backward_branch_target_flag)) { 1135 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); 1136 } 1137 if (cur->loop_depth() == pred->loop_depth()) { 1138 assert(cur->loop_index() == pred->loop_index() || cur->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); 1139 } 1140 1141 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); 1142 } 1143 1144 // check dominator 1145 if (i == 0) { 1146 assert(cur->dominator() == NULL, "first block has no dominator"); 1147 } else { 1148 assert(cur->dominator() != NULL, "all but first block must have dominator"); 1149 } 1150 // Assertion does not hold for exception handlers 1151 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0) || cur->is_set(BlockBegin::exception_entry_flag), "Single predecessor must also be dominator"); 1152 } 1153 1154 // check that all loops are continuous 1155 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { 1156 int block_idx = 0; 1157 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); 1158 1159 // skip blocks before the loop 1160 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1161 block_idx++; 1162 } 1163 // skip blocks of loop 1164 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { 1165 block_idx++; 1166 } 1167 // after the first non-loop block, there must not be another loop-block 1168 while (block_idx < _num_blocks) { 1169 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); 1170 block_idx++; 1171 } 1172 } 1173} 1174#endif 1175 1176 1177void IR::compute_code() { 1178 assert(is_valid(), "IR must be valid"); 1179 1180 ComputeLinearScanOrder compute_order(compilation(), start()); 1181 _num_loops = compute_order.num_loops(); 1182 _code = compute_order.linear_scan_order(); 1183} 1184 1185 1186void IR::compute_use_counts() { 1187 // make sure all values coming out of this block get evaluated. 1188 int num_blocks = _code->length(); 1189 for (int i = 0; i < num_blocks; i++) { 1190 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); 1191 } 1192 1193 // compute use counts 1194 UseCountComputer::compute(_code); 1195} 1196 1197 1198void IR::iterate_preorder(BlockClosure* closure) { 1199 assert(is_valid(), "IR must be valid"); 1200 start()->iterate_preorder(closure); 1201} 1202 1203 1204void IR::iterate_postorder(BlockClosure* closure) { 1205 assert(is_valid(), "IR must be valid"); 1206 start()->iterate_postorder(closure); 1207} 1208 1209void IR::iterate_linear_scan_order(BlockClosure* closure) { 1210 linear_scan_order()->iterate_forward(closure); 1211} 1212 1213 1214#ifndef PRODUCT 1215class BlockPrinter: public BlockClosure { 1216 private: 1217 InstructionPrinter* _ip; 1218 bool _cfg_only; 1219 bool _live_only; 1220 1221 public: 1222 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { 1223 _ip = ip; 1224 _cfg_only = cfg_only; 1225 _live_only = live_only; 1226 } 1227 1228 virtual void block_do(BlockBegin* block) { 1229 if (_cfg_only) { 1230 _ip->print_instr(block); tty->cr(); 1231 } else { 1232 block->print_block(*_ip, _live_only); 1233 } 1234 } 1235}; 1236 1237 1238void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { 1239 ttyLocker ttyl; 1240 InstructionPrinter ip(!cfg_only); 1241 BlockPrinter bp(&ip, cfg_only, live_only); 1242 start->iterate_preorder(&bp); 1243 tty->cr(); 1244} 1245 1246void IR::print(bool cfg_only, bool live_only) { 1247 if (is_valid()) { 1248 print(start(), cfg_only, live_only); 1249 } else { 1250 tty->print_cr("invalid IR"); 1251 } 1252} 1253 1254 1255typedef GrowableArray<BlockList*> BlockListList; 1256 1257class PredecessorValidator : public BlockClosure { 1258 private: 1259 BlockListList* _predecessors; 1260 BlockList* _blocks; 1261 1262 static int cmp(BlockBegin** a, BlockBegin** b) { 1263 return (*a)->block_id() - (*b)->block_id(); 1264 } 1265 1266 public: 1267 PredecessorValidator(IR* hir) { 1268 ResourceMark rm; 1269 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), BlockBegin::number_of_blocks(), NULL); 1270 _blocks = new BlockList(); 1271 1272 int i; 1273 hir->start()->iterate_preorder(this); 1274 if (hir->code() != NULL) { 1275 assert(hir->code()->length() == _blocks->length(), "must match"); 1276 for (i = 0; i < _blocks->length(); i++) { 1277 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); 1278 } 1279 } 1280 1281 for (i = 0; i < _blocks->length(); i++) { 1282 BlockBegin* block = _blocks->at(i); 1283 BlockList* preds = _predecessors->at(block->block_id()); 1284 if (preds == NULL) { 1285 assert(block->number_of_preds() == 0, "should be the same"); 1286 continue; 1287 } 1288 1289 // clone the pred list so we can mutate it 1290 BlockList* pred_copy = new BlockList(); 1291 int j; 1292 for (j = 0; j < block->number_of_preds(); j++) { 1293 pred_copy->append(block->pred_at(j)); 1294 } 1295 // sort them in the same order 1296 preds->sort(cmp); 1297 pred_copy->sort(cmp); 1298 int length = MIN2(preds->length(), block->number_of_preds()); 1299 for (j = 0; j < block->number_of_preds(); j++) { 1300 assert(preds->at(j) == pred_copy->at(j), "must match"); 1301 } 1302 1303 assert(preds->length() == block->number_of_preds(), "should be the same"); 1304 } 1305 } 1306 1307 virtual void block_do(BlockBegin* block) { 1308 _blocks->append(block); 1309 BlockEnd* be = block->end(); 1310 int n = be->number_of_sux(); 1311 int i; 1312 for (i = 0; i < n; i++) { 1313 BlockBegin* sux = be->sux_at(i); 1314 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); 1315 1316 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1317 if (preds == NULL) { 1318 preds = new BlockList(); 1319 _predecessors->at_put(sux->block_id(), preds); 1320 } 1321 preds->append(block); 1322 } 1323 1324 n = block->number_of_exception_handlers(); 1325 for (i = 0; i < n; i++) { 1326 BlockBegin* sux = block->exception_handler_at(i); 1327 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); 1328 1329 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); 1330 if (preds == NULL) { 1331 preds = new BlockList(); 1332 _predecessors->at_put(sux->block_id(), preds); 1333 } 1334 preds->append(block); 1335 } 1336 } 1337}; 1338 1339class VerifyBlockBeginField : public BlockClosure { 1340 1341public: 1342 1343 virtual void block_do(BlockBegin *block) { 1344 for ( Instruction *cur = block; cur != NULL; cur = cur->next()) { 1345 assert(cur->block() == block, "Block begin is not correct"); 1346 } 1347 } 1348}; 1349 1350void IR::verify() { 1351#ifdef ASSERT 1352 PredecessorValidator pv(this); 1353 VerifyBlockBeginField verifier; 1354 this->iterate_postorder(&verifier); 1355#endif 1356} 1357 1358#endif // PRODUCT 1359 1360void SubstitutionResolver::visit(Value* v) { 1361 Value v0 = *v; 1362 if (v0) { 1363 Value vs = v0->subst(); 1364 if (vs != v0) { 1365 *v = v0->subst(); 1366 } 1367 } 1368} 1369 1370#ifdef ASSERT 1371class SubstitutionChecker: public ValueVisitor { 1372 void visit(Value* v) { 1373 Value v0 = *v; 1374 if (v0) { 1375 Value vs = v0->subst(); 1376 assert(vs == v0, "missed substitution"); 1377 } 1378 } 1379}; 1380#endif 1381 1382 1383void SubstitutionResolver::block_do(BlockBegin* block) { 1384 Instruction* last = NULL; 1385 for (Instruction* n = block; n != NULL;) { 1386 n->values_do(this); 1387 // need to remove this instruction from the instruction stream 1388 if (n->subst() != n) { 1389 assert(last != NULL, "must have last"); 1390 last->set_next(n->next()); 1391 } else { 1392 last = n; 1393 } 1394 n = last->next(); 1395 } 1396 1397#ifdef ASSERT 1398 SubstitutionChecker check_substitute; 1399 if (block->state()) block->state()->values_do(&check_substitute); 1400 block->block_values_do(&check_substitute); 1401 if (block->end() && block->end()->state()) block->end()->state()->values_do(&check_substitute); 1402#endif 1403} 1404